I was climbing a single pitch trad climb the other day in the USA (Foster Falls, Tennessee). The rock is sandstone similar to Nowra / Blue mountains, but maybe a bit harder.

My mate climbed up the pitch, which was quite easy, and for practice decided to take a practice fall onto a nut. He backed his fall up with a little two piece equalised anchor under the nut, as well as a cam placed higher with a long runner such that the nut below was in tension during a fall.

He climbed up a very short way, perhaps 1.5 m, and confidently took his fall. I was at the base of the crag watching, with his girlfriend belaying. I saw him fall, and then saw half the damn cliff peel off the wall with him. A piece of rock approximately 1m X 1m X 2m came down right beside the climber and crash onto the ground, destroying my rope!!! Thankfully everyone was positioned at the base of the climb so that we weren't in danger, the climb fortunately had a slight traverse so the belayer was ok but very shaken (missed by 1.5m), the climber was ok as the upper cam on the long runner caught him, everyone was ok!!!

What happened??? We went back up to inspect, he had placed the nut in a perfect placement, but it had caused this whole block to fracture off. I had just climbed the same route and I would never have guessed this piece was loose. You couldn't tap it to listen, it was 1m thick. Fault lines would have been very hard to see as they ran so far (picture looking up over 2m of crack and trying to figure out if it was weak?

Conclusion: ??? Thoughts? My thoughts are that all trad climbers need to be geologists!

On 14/06/2013 jakob wrote:>snip)>I saw him fall, and then saw half the damn cliff peel off the wall with>him. A piece of rock approximately 1m X 1m X 2m came down right beside>the climber and crash onto the ground, destroying my rope!!! (snip)

>What happened??? We went back up to inspect, he had placed the nut in>a perfect placement, but it had caused this whole block to fracture off.>I had just climbed the same route and I would never have guessed this piece>was loose. You couldn't tap it to listen, it was 1m thick. Fault lines>would have been very hard to see as they ran so far (picture looking up>over 2m of crack and trying to figure out if it was weak?>>Conclusion: ??? Thoughts? My thoughts are that all trad climbers need>to be geologists!

Even being a geologist won't help when it comes to a major exfoliation of a cliff.

I have climbed entire rope-length pitches in some trad locations and found that all my pro had been placed in a veneer (sometimes metres thick), waiting to depart*1,2 from the main cliff...

(* 2 I may be wrong with the detail regarding the climb, but I vaguely remember reading about Xaver Bongard and John Middendorf climbing a huge multipitch route on Great Trango Tower, that they called The Grand Voyage, and when they were approaching the topout pitches it shed an entire lower pitch they had earlier climbed, into the abyss below?)

There is a thread on Chockstone running at the moment where it has occurred to me that the enticing-line looks like a booby trap waiting to go off...

There was a recent accident involving a similar 'presumably safe' block...

There's a section of a 'The Nose' on El Cap that is called the 'Bootleg Flake'. I have read it described as a section of rock that doesn't seem to be attached at all? People aid up it all the time.

Apparently when first climbed with nuts it ground under body weight during aid. I am wondering if anyone has ever taken a leader fall on it with a cam and had that 5-6 times fall force expansion outwards?

I am a lot more careful now with cam placements, especially when they are parrallel with the cliffline.